Recall 18V521 affects 14 2016-2017 Byd K11 M buses for brake caliper guide pin bolt breakage. Repair is free at any franchised Byd dealer.
Byd is recalling 14 2016-2017 K11 M hybrid electric transit buses because roughness on a radial brake caliper guide pin can break the support bolt. If that pin fails, the bus can lose braking ability or tire pressure and increase crash risk; the dealer repair will be free once available.
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What's wrong?
The air disc brake caliper on the 2016-2017 Byd K11 M is part of the brake assembly on the ZF center axle. The caliper squeezes brake pads against a disc when air pressure applies the brakes. Guide pins let the caliper carriage move in a controlled path so braking force stays even.
On affected buses, a guide pin inside the Knorr-Bremse radial brake caliper was finished with improper surface roughness. That rough pin adds stress to the brake carriage guide pin support bolt. Over normal service, the extra stress can fracture the bolt and interfere with the caliper's movement. When the brake hardware does not move correctly, braking performance is reduced and stopping distance increases.
The warning sign listed for owners is noise from the axle area. A new or unusual sound near the center axle is the signal to report before the bus returns to service.
Who's affected?
Spans the K11 M across the 2016 and 2017 model years, with the brake system listed for each year.
| 2017 Byd K11 M | brake system |
|---|---|
| 2016 Byd K11 M | brake system |
| Units affected | 14 |
| Field incidents | NHTSA has logged 13 field incidents to date. |
A matching year and model does not guarantee inclusion. Check your VIN to confirm whether your specific bus is included.
What's the safety risk?
A broken guide pin can cause loss of braking ability or loss of tire pressure, increasing crash risk. Treat noise near the axle as a reason to slow down, stop in a safe place, and call a franchised Byd dealer. Repair will be free at any franchised Byd dealer once available.
What should I do?
- Check your VIN to confirm your 2016-2017 Byd K11 M is included in this recall.
- Find the Byd owner notice mailed on October 11, 2018, if you have it.
- Contact a franchised Byd dealer about the free bushing-kit installation and brake-caliper reinstallation that fixes the guide-pin bolt problem.
- Reference recall number 18V521 when you call the dealer or Byd customer service.
- Drive with extra caution until the repair is complete, since guide-pin breakage can reduce braking ability or tire pressure.
What happens at the repair
At the dealer, a Byd technician will install a bushing kit, then reinstall the brake calipers so the caliper hardware is properly supported. Parts and labor will be covered under the recall once the remedy is available. Byd has a general reimbursement plan on file for owners who already paid for a related brake caliper repair before the recall notice. Keep invoices and proof of payment, and ask Byd customer service or the service desk how to submit the documentation under the manufacturer's standard reimbursement plan.
| Reimbursement | Reimbursement available |
|---|
Timeline
| August 7, 2018 | NHTSA published the recall |
|---|---|
| September 4, 2018 | Interim owner notification (was planned for this date) |
| October 11, 2018 | Owner notification mailed |
Frequently asked questions
What is recall 18V521?
Recall 18V521 covers 14 2016-2017 Byd K11 M hybrid electric transit buses with ZF axles and radial air disc brakes. A rough guide pin in the brake caliper can break the guide pin support bolt, causing loss of braking ability or tire pressure. Byd dealers install a bushing kit and reinstall the brake calipers for free.
What should I do if my 2016-2017 Byd K11 M is on this recall?
Check your VIN to confirm your specific bus is included in recall 18V521. If it is, contact a Byd dealer to schedule the bushing kit installation and brake caliper reinstallation. The recall began October 11, 2018, and Byd customer service is available at 1-661-940-3250.
Is the recall repair free?
Yes. Federal recall law requires the manufacturer to repair the defect at no cost. For recall 18V521, Byd dealers install the bushing kit and reinstall the brake calipers free of charge.
What is the safety risk?
The safety risk is reduced braking ability or loss of tire pressure if the brake carriage guide pin support bolt breaks. Either condition can raise crash risk. If your VIN is included, arrange the free dealer repair before putting the bus back into regular service.
More information
| NHTSA campaign page | nhtsa.gov/vehicle-recalls/18V521000 |
|---|---|
| Byd customer service | 1-661-940-3250 |
| NHTSA recall # | 18V521 |
| NHTSA recall # (full) | 18V521000 |
Source documents
This article is generated from NHTSA's primary recall filings and reviewed against the source on May 25, 2026. RecallNotify does not paraphrase NHTSA's consequence language; that text is reproduced as written above. Editorial standards →